Heavy difficulties were encountered in this last decade by a number of industrialized countries in competing in the maritime transportation field. A more sophisticated technology of maritime transport, finalized to reach higher productivity is requested to allow industrialised countries to profitably manage maritime transportation in the proximate future.
In the sixties a relevant increase of productivity was achieved in many sections of maritime transport, due especially to the ship mammothing trend. This trend has brought up the ship to encounter the harbour depth in many areas of the world. Waterborne crude oil tankers overcame this problem by being moored at an open sea pipeline terminal, but in the solid bulk raw material transport the harbour depth represents today one of the biggest restraints to further increase the ship size and consequently the transport productivity. Another restraint is the way unloading operations are carried out; particularly the intermittance in the flow of cargo from ship to shore and the repetitive translations and movements of the bucket are a bottleneck in transport productivity and also a source of atmospheric pollution.
The harbour infrastructure in fact represents today the biggest restraint to the increase in transport productivity. Modifications at the harbour structures to cope with the new traffic requirements would require very long time and also very huge investments; these on the other side are not always justified as they would advantage only a section of the industry while their weight is supported by all the collectivity.
The system object of the present invention relates to massive solid bulk raw material transport and provides a substantial increase in the maritime transport productivity by requesting minor modifications in the harbour structure.
During the past years a number of significant technological developments were carried out on the united cargo transportation to solve the interface problems between maritime and piggy-backing or river transport. Container vessels and barge carrier vessels were built and also flotation loading and unloading of barges through a gate on the vessel were developed. Some embodiments were also proposed for having barges stowed in a number of layers in the hold of the carrier vessel but the solutions proposed call for very costly structure of the carrier vessel and elaborate operations for loading and unloading of barges.
Accordingly, it forms the main object of the present invention to provide a new system and method of transport such that barges could be stacked one on the other into the hold of the carrier vessel in the same way as containers are stacked into the container ship. For reaching this target barges are to be perfectly watertight and have no hatches; consequently the loading and unloading operations of the cargo into the barges can no more be done as usually by means of buckets moved by travelling cranes but by having barges put in a sloping trim and cargo moved and transferred by its own weight.
A further object of the present invention is the barge carrier vessel itself whose structure, fittings and arrangements have to allow the stacking operation of barges into the hold.
Thus, main objects of the present invention are:
to provide an improved maritime transportation system employing a novel type of barge; the barge-container, having no hatches, being perfectly watertight and capable to be stacked one on the other; to provide a novel type of loading and unloading of the cargo into the barge container in which the barge container is placed on a sloping trim and the cargo is moved and transferred by its own weight; to provide an improved barge carrying waterborne vessel in which barge containers are stacked one on the other in a multilayer configuration, and the vessel itself is capable to be overimmersed in a proper dredged area in the harbour basin for flotation loading and unloading.